Human Biology Year 1 Semester 1 Midterm 1 - Cells

Flashcards by michellelynnlebl, updated more than 1 year ago


University Human Biology Flashcards on Human Biology Year 1 Semester 1 Midterm 1 - Cells, created by michellelynnlebl on 09/29/2014.

Resource summary

Question Answer
What are the two kinds of cells? Procaryotes and eucaryotes.
What are the two domains of Procaryotes (bacteria)? Archaebacteria & Eubacteria
Do Procaryotes have a nucleus? Do they have membrane bound organelles? No No
True or False: Procaryotes were the first cells and they are single-cell organisms. True
What is Peptidoglycan ? Protein in plasma membrane of some prokaryotes, but no eukaryotes.
What is the one domain of Eukaryotes? Eukaryia
What is the endosymbiotic theory? The endosymbiotic theory states that several key organelles of eukaryotes originated as symbioses between separate single-celled organisms. (wikipedia)
What are single, colonial and multicellular organisms? Single- one nucleated cell Colonial- each cell isn't specialized and does all of the work, but they live in groups. Example: moss. Multicellular- each cell is specialized and couldn't survive on its own. (ex:humans)
Where is the DNA located in eukaryotes? Procarkyotes? Eukaryotes: Nucleus Prokaryotes: All throughout cytoplasm
True or False: eukaryotes have membrane bound organelles. True
True or False: There a difference in the plasma membrane of pro and eukaryotes True
What is haploid? Diploid? Haploid (n): Set of chromosomes from one donor, gametes, asexual reproduction, haploid organisms (reproduce by mitosis) Diploid (2n): Set of chromosomes from 2 parents, each type of chromosome in pairs, somatic cell type of diploid organisms.
True or False- Do animals and plants both have mitochondria and chloroplasts? False. Plants have both; animals only have mitochondria.
What is mitosis? Cytokinesis? Meiosis? Mitosis-DNA replication and division. Cytokinesis- Division of cell components Meiosis-Production of gametes (sex cells) [only diploid organisms can go through meiosis]
3 points of Prokaryotic Division -Binary fission -Circular DNA -Fts2 molecule is the trigger for separation
3 points of eukaryotic chromosomes -House the genes -Made of DNA and proteins (chromatin) -Tightly coiled
What is DNA coiled around? Histone molecule (nucleosome)
What is a group of nucleosomes called? Solenoid
What forms a chromatin loop? Long strips of solenoids
What do many chromatin loops form? Many loops form a rosette anchored to the chromosome core by a scaffold protein
Eukaryotic chromosomes have a centromere. Where is it located and what is it the attachment site for?I Its location is unique to that chromosome and it is the attachment for spindle fibres.
What is the protein that spindle fibers attach to? Kinetochore
What is a chromosome? Where DNA is housed. Structure consisting of DNA and histone of same gene.
Define: centromere Site of DNA synthesis; where sister chromatids come together.
Define: Chromatid 2 identical strands of replicated DNA (sister chromatids)
Define: Homologous 2 chromosomes of same type from different parent
Define: Haploid (n) Genetic info. came from a single donor
Define: Diploid (2n) Genetic info. came from 2 donours.
What is trisomy & monosomy ? Trisomy: 3 chromosomes of same type Monosomy: 1 chromosome instead of 2
Define: Cell cycle Time that is spent in each phase of the cells life
What are the phases of interphase? Mitosis? And what follows mitosis? Interphase: G, S, G2 Mitosis: Prophase, Metaphase, Anaphase, Telophase. (PMAT) Cytokinesis
What do the checkpoints determine? What are they? (regulating the cell cycle) Checkpoints determine if cell moves to the next phase of the cell cycle. -G2, M checkpoint -Spindle checkpoint -G1,S checkpoint (start or restriction checkpoint)
Name 3 factors that influence the check at the checkpoints. Nutrition, size, health
What stage do cells often get stuck in and stay for long periods of time? When they get stuck in G1 for an extended period of time, it is called G0(zero). Some cells never leave this stage.
What happens at the G1 restriction point? The cell decides to divide or not. Arrest at this point results in G0(zero).
What happens at the G2/M checkpoint? At the end of G2 phase. CDK (cyclin dependent kinase) active at this pointand allow movement into M-phase. DNA checked for proper replication.
What happens at the spindle checkpoint? Check that all chromosomes are attached to spindles for anaphase.
What does CDK stand for? Cyclin dependent kinase
What are proteins activated by and what does this allow? Proteins are activated by phosphorylation on the enzyme thus allowing passage through the checkpoint.
True or false- Each checkpoint has its own cyclins True
Define mitosis. State what it produces. For growth and repair. This occurs in both diploid and haploid cells. DNA replication and division of somatic (autosomal) cells. One cell produces 2 identical cells (identical to parent and each other)
Does crossing over of alleles occur in mitosis? What is conserved? Crossing over of alleles (genetic info.) does not occur in mitosis. Genetic info. is conserved.
What are the 4 phases of mitosis and what is it followed by? P- Prophase M- Metaphase A- Anaphase T- Telophase Followed by cytokinesis.
What is meiosis? What does it produce? Division of germ cells. The production of sex cells (n), called gametes (only half the chromosomes of parent) from germ cells 2n (diploid.
What does meiosis start with and what does it end with? Start with 1 diploid and end with 4 haploid cells.
Name the 6 major differences between Mitosis and Meiosis. In notes. (too much to type out)
What happens and what is produced in: Meiosis I: _____ Meiosis II: _______ What are the final products? Meiosis I: tetrads separate into sister chromatids (resulting cells are haploid) Meiosis II: separates sister chromatids so that each cell gets one chromosome (resulting in unpaired sister chromatids) Products: 4 haploid gametes (sex cells) that are not identical to each other or the parent cell.
<- Label blank_model_of_synaptonemal_complex.jpg (image/jpg) model_of_synaptonemal_complex.jpg (image/jpg)
What is the chiasma? Where nodules do crossing over
Fill in the blanks blank_meiosis.jpg (image/jpg) meiosis.gif (image/gif)
Complete: Meiosis II resolves the ____________. 4 _______ cells. Meiosis II resolves the original DNA replication. 4 haploid cells.
How does recombining of genetic info. occur? Recombining of genetic information by segregation, random orientation of chromosomes, and crossing over
Where does variation originally occur? What does it create? Variation originally comes from mutations in DNA synthesis in germ cells which create new phenotypes
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